package com.boyunv.observer.example01;
/*
 *@description
 * 抽象目标类
 *@author boyunv
 *@create 2023/8/11 7:39
 *@version 1.0
 */

public interface Subject {
  void  attach(Observer observer);
  void  detach(Observer  observer);
  void  notifyObservers();
}
